Characterization of Cobalt Films on X-Ray Lithographic Micropillars
Arrays of SU-8 photoresist pillars (10 μm ×10 μm × 50 μm) on copper substrates were fabricated by X-ray lithography. The photoresist-coated substrates were irradiated by X-ray from a synchrotron source through patterned silver dots on a graphite mask. After the resist development, the chemically stable and mechanically hardened SU-8 pillars exhibited smooth vertical sidewalls and cross section with up to 10 % dimensional errors from the designated pattern. Cobalt of thickness ranging from 50 to 80 nm was then deposited on these patterned substrates by RF sputtering. These cobalt films on SU-8 pillars showed a lower in-plane magnetization than that of continuous cobalt films because of their smaller grain size. The measurement with out-of-plane magnetic field gave rise to a higher magnetization and this anisotropic behavior was observed only in cobalt-coated pillars.
Yun-Hae Kim, Prasad Yarlagadda, Xiaodong Zhang and Zhijiu Ai
P. Sukonrat et al., "Characterization of Cobalt Films on X-Ray Lithographic Micropillars", Advanced Materials Research, Vols. 335-336, pp. 1000-1003, 2011